1. Field of the Invention
The present invention generally relates to devices and methods for actuating or controlling one or more downhole tools or devices. In particular embodiments, the invention relates to actuation or control of a downhole device using a vibration-based trigger signal.
2. Description of the Related Art
During hydrocarbon production, a number of downhole devices are used which must be actuated or controlled from surface. In certain instances, it is impractical to run electrical, communications or even hydraulic fluid control lines to the downhole device. Another method is to transmit wireless signals such as vibrations, pressure pulses, flow pulses or electromagnetic waves along the casing or through well fluid down to the device in the wellbore. Vibrations generated at the surface can be practically transmitted along the metal casing lining the wellbore or through the annulus fluid and used as a signaling method to control downhole devices. However, fluid bubbles, discontinuities and other obstructions will dissipate surface-generated vibratory signals before they can reliably travel to deeper locations in a wellbore.